[c-nsp] ip unnumbered

[Charles Sprickman]

On Dec 5, 2012, at 3:57 AM, zaid wrote:

> hi 
> 
> I can't access the internet when config ip unnumbered on the
> subinterface, any idea this is my config

> 
> interface Loopback1
>  ip address x.x.x.x 255.255.255.255

Is that really the subnet you're using?  If so, what IP are you
giving the device on vlan 44?

> 
> interface GigabitEthernet1/13.15
>  encapsulation dot1Q 44
>  ip unnumbered Loopback1

If you keep this the same and give the loopback a mask that allows
for more than one IP, it should work as long as you add a route
pointing to the interface.  This is very similar to the old dsl
termination configs actually.

An example based on something we have setup and working:

in loopback 1
 ip address 10.1.1.1 255.255.255.0

in gi1/0.102
 encaps dot1q 102
 ip unnumbered loop 1

ip route 10.1.1.2 255.255.255.255 gi1/0.102

The device off that vlan would have an IP of 10.1.1.2/24, gateway of
10.1.1.1.

Here's some info: 

http://blog.ioshints.info/2010/02/unnumbered-ethernet-vlan-interfaces.html

http://www.cisco.com/en/US/docs/ios/12_3t/12_3t4/feature/guide/gtunvlan.html

Charles

>  ip ospf 1 area 
> 
> * ping the internet with loopback 1 as as source working 
> 
> * my pc is the same ip of loopback 1
> 
> HZ
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